1. Field of the Invention
The invention relates to a display apparatus, more particularly relates to an on-screen display apparatus which is capable of superposing and displaying an image based on a sub image data on an image based on a main-image data.
2. Description of the Related Art
A photographic apparatus such as a digital still camera and a digital video camera has, conventionally, an OSD (On-Screen Display) function of superposing a sub-image including characters such as letters based on a sub-image data on a main image such as an object image based on a main image data, and then displaying them on a display section such as a liquid crystal display (LCD) or the like. With recent advance in digital camera performance, the number of sub-image data superposed and displayed increases.
As an on-screen display apparatus which decreases CPU load without requiring a frame memory, there have been known a display control apparatus which reads out character data from a character memory and then displays them on a display apparatus (Japanese Patent Application Laid-Open (JP-A) No. 11-212539), and an on-screen display apparatus which outputs a sub-image signal using a ROM for OSD for storing pattern data such as a character font, by means of the sprite technique for use in game apparatuses, etc. ((JP-A) No. 9-205597).
However, the above-mentioned technique of JP-A No. 11-212539 has a problem that the display control apparatus cannot superpose and display the plural character data because it reads out the character data and then outputs the read out data on the display apparatus.
The above-mentioned technique of JP-A No. 9-205597 has a problem that the on-screen display apparatus requires the ROM for OSD for storing the pattern data such as the character font, which increases costs, and the apparatus cannot superpose and display the plural character fonts.
The present invention has been made in order to solve the above-mentioned problems; therefore, it provides a display apparatus, which is at a low cost in configuration, and is capable of displaying an image with the plural sub-image data superposed.